Determination of amprenavir, a HIV-1 protease inhibitor, in human seminal plasma using high-performance liquid chromatography–tandem mass spectrometry

A HPLC–MS–MS method to measure amprenavir in human seminal plasma has been developed and validated. The procedure uses stable, isotopically labeled 13C6-amprenavir as an internal standard and 100 μl of sample. The method is accurate (bias less than or equal to 7.2%) and precise (within- and between-day RSDs less than or equal to 4.2%) over the dynamic range of 30–4000 ng/ml. Recently, this simple and sensitive method was used to determine amprenavir concentrations in seminal samples collected from HIV-1 positive subjects receiving amprenavir antiretroviral therapy as part of a multicenter clinical trial.